I searched for this answer and could not find it. I am not sure which brand of furnace I have. When I opened the cover it says the model number is G1N80AT100D14B-2. My furnace works great on heat. Now that it is hot outside I would like to run the fan setting to get some extra circulation in the house. I don't have A/C. How do I hookup my furnace to only operate the fan? I tried using the "on" setting on the thermostat on both the heat and cool setting but that didn't work. I am a novice so please walk me step by step. I am hoping I just switch one of the jumpers on the circuit board. By the way, I don't believe that my thermostat is even hooked up to the cool setting at all. Thanks in advance!